User`s guide

Chapter 9 LAN Setup
P-2602HWUDL-D User’s Guide
147
With the Any IP feature and NAT enabled, the ZyXEL Device allows a computer to access the
Internet without changing the network settings (such as IP address and subnet mask) of the
computer, when the IP addresses of the computer and the ZyXEL Device are not in the same
subnet. Whether a computer is set to use a dynamic or static (fixed) IP address, you can simply
connect the computer to the ZyXEL Device and access the Internet.
The following figure depicts a scenario where a computer is set to use a static private IP
address in the corporate environment. In a residential house where a ZyXEL Device is
installed, you can still use the computer to access the Internet without changing the network
settings, even when the IP addresses of the computer and the ZyXEL Device are not in the
same subnet.
Figure 103 Any IP Example
The Any IP feature does not apply to a computer using either a dynamic IP address or a static
IP address that is in the same subnet as the ZyXEL Device’s IP address.
" You must enable NAT/SUA to use the Any IP feature on the ZyXEL Device.
9.3.4.1 How Any IP Works
Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol address (IP
address) to a physical machine address, also known as a Media Access Control or MAC
address, on the local area network. IP routing table is defined on IP Ethernet devices (the
ZyXEL Device) to decide which hop to use,
to help forward data along to its specified
destination.
The following lists out the steps taken, when a computer tries to access the Internet for the first
time through the ZyXEL Device.
1 When a computer (which is in a different subnet) first attempts to access the Internet, it
sends packets to its default gateway (which is not the ZyXEL Device) by looking at the
MAC address in its ARP table.
2 When the computer cannot locate the default gateway, an ARP request is broadcast on
the LAN.
Internet
192.168.1.1
192.168.10.1
Internet
192.168.10.1